Many decorative and protective functions are served by extruded polymeric trim strips. A preferred strip design involves the coextrusion of a decorative metal foil of aluminum or other bright metal with a thermoplastic polymer such as plasticized polyvinyl chloride, chlorinated polyethylene, or ionomeric resins.
Such strips generally have a decorative contoured upper show surface and a relatively flat bottom surface adapted for mounting on a substrate. They may be used, e.g., as automotive body side moldings to protect body panels from impact damage. When the ends of a strip are cut at square or tapering angles, raw metal foil edges are exposed. It is desirable to seal these edges to prevent corrosion. They are preferably coated with an opaque paint which both seals and conceals the foil. Because such paint may be unsightly if it laps onto a decorative strip surface, paint masks have heretofore been used in the end finishing operation. The masks are cut to match the shape of the end. This method obviously entails the use of a different mask for each strip contour and cut angle. Moreover, unless the mask is kept clean and tightly secured to a strip during the paint operation, a good clean paint edge may not be achieved.